ESP32 custom Board w/ UART - no serial feedback

[Danjoh]

Hi there,

I have designed a custom PCB (my first one) with an ESP32, UART Bridge and some sensors.

I am able to connect it, and even to upload some code (with pushing the boot button).

However u don’t get any signal feedback on the serial.monitor. I tried different settings in Arduino IDE and Platform.IO.

Do you have any Tipp where I should looking at? I am really tying hard but can’t find the issue.

According to the BOM we have an ESP32-S3-WROOM-1-N8

[ves011]

How do you know you are able to load the code?
Maybe its an issue with the way you generate rts/cts signals. I would try to use directly internal USB/JTAG i/f on pins 19/20. If i understood correctly your schematic, it just need a small rework.
This way you eliminate usb/uart bridge and be sure esp32 is booting properly.

[Danjoh]

I setup the Arduino IDE as shown in the screenshot + the build and upload was successful at least according to the screenshot.

I tried to keep the code as clean as possible.

Code: Select all

void setup() {

  Serial.println("Hello World");
}

void loop() {
}

however I also tried it with Serial-println in the loop.

Regarding your tip. I need to cut a USB cable, attach the data cable to GPIO19 and 20 and try the same right? or which setting is required for this?

thank you very much!

[ves011]

Looks OK!
Not sure if you have a Serial.begin(); in your setup code.
If you have it and still not working, then try the usb cable.
Either you cut it and solder directly D+/D- and GND wires, or let it as it is, remove R46, R47 and place R18, R19 and plug it in the connector.

[Danjoh]

Hi Ves011,

it looks like this was a good hint. Once I have connected GPIO 19 (white USB cable) and GPIO20 (green USB cable) I was immediately getting a serial output. I used the USB-C in parallel to "power" the PCB.

Learn so far:

- The former upload was successful as I can see the old program running
- The serial output is only working via GPIO 19 and 20.

Do you have any hint what can be the cause here?

Thank you very much!